Combustion air control in an in-line flame arrestor

Abstract

Mounted on the entrance end of a firetube, the two screen elememts of an in-line flame arrestor are linearly spaced along a tubular core. A common aperture through the core wall is formed between the two screens. Combustion air directed through either, or both, screen elements enters the core through the aperture in the core wall to supply a fluid-fuel burner mounted within the core both primary and secondary portions of the combustion air. The effective size of the aperture is adjusted by a movable, internal sleeve within the core with linkage to the fuel supply system of the burner.

We claim: 
     
       1. A flame arrestor and combustion air control combination, including, an elongated cylindrical firetube into which combustion is to be propagated,   a hollow cylindrical core sealed by a first end to the entrance of the firetube,   a removable base plate mounted on and sealing the second end of the core,   a burner mounted on the base plate and within the core as a housing to propagate combustion into the firetube,   an aperture through the wall of the cylindrical core through which combustion air flows to the burner,   two spools of flame arrester screen mounted on the core, one on each side of the aperture,   a sheath mounted about the two screen spools and sealed to the spool peripheries to limit combustion air flow to paths through both screens and down through the common aperture between the screens and into the cylindrical core,   a sleeve positioned within the cylindrical core to establish the effective size of the aperture in the path of the combustion air,   a linkage between the sleeve and the base plate powered by fluid pressure to increase the size of the aperture by movement of the sleeve,   a spring connected between the sleeve and the core to generate a force urging the sleeve in a direction to reduce the size of the aperture, and   a connection between the sleeve and the pressure of the fuel supplied the burner as power to actuate the linkage,   whereby the quantity of fluid fuel supplied the burner has its pressure applied to position the sleeve in adjustment of the quantity of air supplied the burner through the aperture to propagate the combustion by the burner.   
     
     
       2. The combination of claim 1, wherein, the linkage between the sleeve and base plate includes a piston/cylinder and the sleeve is connected to the fluid pressure to move the piston in the direction which will urge the sleeve to enlarge the aperture.   
     
     
       3. A combined flame arrestor and burner housing module with which to propagate combustion into a volume to be heated, including, a tubular core/housing mounted by a first end to propagate combustion into a space to be heated,   a base plate detachably sealed to the second end of the core/housing   a burner mounted on the base plate and extending within the tube toward the first end to propagate combustion into the space to be heated,   a supply of fluid fuel connected to the burner,   an aperture through the wall of the core/housing intermediate the first and second ends,   a cylindrical sleeve slidable within the core/housing having a range of travel within the core/housing to adjust the effective opening of the aperture,   a linkage between the sleeve and the base plate to position the sleeve along its range of travel,   a connection between the fuel supply and the linkage to convert the pressure of the fuel supplied the burner to mechanical motion in positioning the sleeve,   whereby the quantity of fuel supplied the burner as represented by the pressure regulates the amount of combustion air supplied the burner through the aperture to provide efficient combustion propagated by the burner.   
     
     
       4. The module of claim 3, including, a spool of screen sealed to the external surface of the core/housing, one on each side of the aperture, and   a sheath sealed to the external periphery of each spool to confine access of combustion air to the aperture through the spools.   
     
     
       5. The module of claim 3, in which, the linkage comprises a piston/cylinder combination connected between the base plate and the sleeve and a spring between the sleeve and the core,   whereby the piston/cylinder is powered by the fuel pressure to urge the sleeve to increase the opening of the aperture and is in opposition to the resilient force generated by the spring.